1. Field of the Invention
This invention relates to upright water extraction cleaning machines and, more particularly, to an improved float assembly for an upright water extraction cleaning machine.
2. Description of the Related Art
Water extraction cleaning machines have long been used for removing dirt from surfaces such as carpeting, upholstery, drapes, and the like. The known water extraction cleaning machines can be in the form of a canister-type unit as disclosed in U.S. Pat. No. 5,237,720 to Blase et al. or an upright unit as disclosed in U.S. Pat. No. 5,500,977 to McAllise et al. and U.S. Pat. No. 4,559,665 to Fitzwater.
Water extraction cleaning machines generally include a recovery tank for containing the separated recovered fluid and debris from the working air stream after pick up by a nozzle at the end of a suction conduit remote from the recovery tank. The dirty air, liquid, and debris is sucked to the recovery tank from the nozzle and the liquid and debris separates from the working air stream and are retained within the recovery tank. The liquid and debris-free working air stream, or clean exhaust air, is released from the tank through an outlet port formed in a top portion of the recovery tank, preferably above the level of water within the recovery tank. This liquid and debris-free working air stream passes through the outlet port and an exit conduit under suction pressure from a vacuum source coupled to the outlet port of the recovery tank. After passage through the vacuum source, the clean exhaust air is permitted to escape through exhaust openings within the extraction cleaner housing to which the recovery tank is mounted.
There are several known methods of preventing the liquid and debris recovered in the tank from escaping the tank through the outlet port for the clean exhaust air. Baffles installed within the recovery tank between the recovered liquid and debris level and the exit port inhibits sloshing recovered liquid in the tank from accessing the outlet port. These devices are unreliable because a baffle always induces openings for the passage of recovered fluid and debris. The openings permit recovered fluid to reach the outlet port in an overfill condition; that is, when the recovered fluid reaches the height of the outlet port in the recover tank. A better device is a float shut-off assembly, which consists of a floating member contained within a riser tube and rising with the level of the recovered liquid and debris in the tank cover the outlet port when the recovered liquid reaches a pre-determined height below the outlet port. The object of these devices is to prevent water from entering the outlet port, whereupon it would be sucked into the vacuum pump and within reach of its electrical drive motor, which could be damaged by exposure to liquid. Thus, the reliability and quality of the seal provided by the float mechanism is of primary importance.